The active Sennheiser AC 3 Antenna Combiner is the opposite of an antenna splitter. Much like the ASA 1 splitter, the Sennheiser AC 3 combiner allows In-Ear Monitor (IEM) transmitters to share an antenna as well as to get power distribution. The idea is to clean up the antenna farm and alleviate the problems inherent in having multiple antennas in the same area. The Sennheiser AC3 combines up to 4 Sennheiser evolution wireless IEM transmitters.